Effects of Particle Size and Polydispersity on the Depletion and Structural Forces in Colloidal Dispersions

Langmuir ◽  
1996 ◽  
Vol 12 (21) ◽  
pp. 5004-5010 ◽  
Author(s):  
X. L. Chu ◽  
A. D. Nikolov ◽  
D. T. Wasan
Keyword(s):  
Particle Size ◽  
Colloidal Dispersions ◽  
Structural Forces

STRUCTURAL PARAMETERS OF AQUEOUS COLLOIDAL DISPERSIONS OF FULLERENE C60

2019 ◽  
pp. 31-37
Author(s):  
V.Yu. Fokina ◽  
E.А. Kizima ◽  
I.V. Miheev ◽  
A.I. Ivankov ◽  
V.M. Garamus
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Particle Size Distribution ◽  
Structural Parameters ◽  
Colloidal Dispersions ◽  
Fullerene C60 ◽  
Solvent Exchange ◽  
X Ray ◽  
Dense Nucleus ◽  
Exchange Technique

Two types of fullerene C60 water dispersions were investigated by a small-angle X-ray and neutron scattering. As a result, structural parameters of fullerene aggregates were obtained. The water dispersions were obtained by the solvent-exchange technique and by huge dilution of initial C60/Nmethylpyrrolidone solution. The structure organization of water dispersions is considered in respect to their technique preparation. It was shown that fullerene aggregates were characterized by highly polydispersity in size for all dispersions. In the case of son/nC60 dispersion it was found that fullerenes formed aggregates with a dense nucleus (namely a surface fractal) with a radius of 58 ± 1 nm and a fractal dimension of 2.3. In turn, the nmp/nC60 system was characterized by the branched aggregates with fractal dimension 1.5 and bimodal particle size distribution.

scholarly journals Optimized Birch Bark Extract-Loaded Colloidal Dispersion Using Hydrogenated Phospholipids as Stabilizer

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 832 ◽  
Author(s):  
Francis Kamau Mwiiri ◽  
Rolf Daniels
Keyword(s):  
Particle Size ◽  
Interfacial Tension ◽  
Profile Analysis ◽  
Average Particle Size ◽  
Colloidal Dispersions ◽  
Wound Dressings ◽  
Bark Extract ◽  
Phospholipid Content ◽  
Birch Bark ◽  
Average Particle

This study investigated the formulation and processing of aqueous colloidal dispersions containing a birch bark dry extract (TE) as the active substance and hydrogenated phospholipids (Phospholipon 90H) as stabilizer, which can be used in the preparation of electrospun wound dressings. Colloidal dispersions manufactured using a two-stage homogenization process had a bimodal particle size distribution, which was most significantly (p < 0.0001) affected by the phospholipid content. The size of the single particles decreased from an average particle size of about 4 µm to a particle size of approximately 400 nm. Dynamic interfacial tension studies performed using a profile analysis tensiometer (PAT) showed that the phospholipids strongly declined the interfacial tension, whereas a further decrease was observed when phospholipids were combined with birch bark extract. Interfacial viscoelasticity properties analyzed using the oscillating drop technique resulted in an increase of both interfacial elasticity and viscosity values. These results indicated that the phospholipids are preferentially located at the lipophilic/water interface and a stable film is formed. Furthermore, the results point to a synergistic interaction between phospholipids and TE. Confocal Raman microscopy (CRM) suggested that the TE is predominantly located in the oil phase and the phospholipids at the interface.

The formulation of pesticides for convenience and safety

1973 ◽  
Vol 7 (5) ◽  
pp. 231-235 ◽  
Author(s):  
G J Marrs ◽  
M R Middleton
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Colloidal Dispersions ◽  
Wide Range

The user wants pesticides that are convenient, safe and effective. The most commonly used types of formulation—dusts, aqueous solutions, dispersible powders and emulsifiable concentrates—all have their limitations. More sophisticated formulations have been developed which offer reduced handling hazards and provide better control of placement and persistence. These include granules, colloidal dispersions and encapsulated formulations with a wide range of particle size.

scholarly journals Concentration and Dilution of Ultrafine Bubbles in Water

2020 ◽  
Vol 4 (4) ◽  
pp. 50
Author(s):  
Shunya Tanaka ◽  
Yuri Naruse ◽  
Koichi Terasaka ◽  
Satoko Fujioka
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Particle Tracking ◽  
Practical Problem ◽  
Colloidal Dispersions ◽  
Number Concentration ◽  
Ultrapure Water ◽  
Rotary Evaporation ◽  
Dispersion Media ◽  
The Stability

Submicron-sized bubbles are now officially called ultrafine bubbles (UFBs) by the international standard. The concentration of UFBs is generally low (<109 particles/mL; <0.001 vol%) compared to other colloidal dispersions. To overcome this practical problem, we concentrated UFBs in ultrapure water prepared by a commercial UFB generator and quantified the effect of rotary evaporation of the dispersion media on the stability of UFBs. The UFB dispersions were characterized by a particle tracking analysis (PTA) instrument. The experimental results showed that the UFBs can be diluted and concentrated without changing the size distribution and there was little or no loss of UFBs. By using a rotary evaporator, UFB dispersions were about 30-fold concentrated and the resultant number concentration reached over 3 × 1010 particles/mL. Increasing the concentration of UFBs allowed for satisfactory dynamic light scattering (DLS) measurements. The differences among the three algorithms for analyzing the raw data, i.e., autocorrelation function, obtained by DLS are discussed, along with the characteristics of the particle size distribution derived from each algorithm.

Light transmission instrument for particle size analysis of colloidal dispersions

1980 ◽  
Vol 27 (2) ◽  
pp. 215-218
Author(s):  
R.J.M. Tausk ◽  
H.C.J. Venselaar ◽  
H.C. Corbet ◽  
P.N. Wilson
Keyword(s):  
Particle Size ◽  
Light Transmission ◽  
Particle Size Analysis ◽  
Colloidal Dispersions ◽  
Size Analysis
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